The 2015 Audi RS3 is expected to stray away from its five-cylinder turbo roots, and will likely be fitted with a newly-developed high-output four-cylinder turbo.

Audi RS3 2

The new-generation Audi RS3 had been spotted by our European spies already, and those mules were fitted with burbling five-cylinder turbo engines. However, CarAdvice's sources now claim the RS3 prototype seen here "sure does sound like a four-cylinder".

That would make sense as Audi could feasibly use the 2.0-litre four-cylinder turbocharged engine that recently debuted in the Volkswagen Golf R 400, which produces a huge 295kW of power and 450Nm of torque - up on power compared to the five-cylinder engine, but slightly down on torque (265kW/465Nm in TT RS guise).

Audi RS3 1

If it were to be fitted with a four-cylinder rather than a five-pot it would contradict what CarAdvice was told earlier this year when Audi's head of convertible development Mario Weiland said "I think the decision has been made," regarding retaining the five-cylinder mill.

In terms of styling changes over previous spied prototypes it appears this RS3 features wider wheel arches, while its broad bumper with gaping air intakes, low front splitter and high-tech LED headlights look production-ready. At the rear, the prototype has changed from quad exhaust tips to dual outlets with oval-shaped tips.

The new Audi RS3 is expected to debut at the Paris motor show in October, with production likely to start in late 2014. The car is expected to be sold locally, with deliveries commencing in 2015.

Audi RS3 5

Click the Photos tab above for more images of the Audi RS3.